A package of this type is known from French patent No. FR 2 499 025. In that package, the first sheet is provided with two parallel tear strips and the pull corner is formed by a 45° fold of two halves of one of the sides of the cut-out sheet. The effect of this folding is to be bring the ends of the two tear strips into a heat-sealing zone that is relatively far away from the end of the pull corner. When the pull corner is pulled, there is a danger of tearing the pull corner before exerting traction on the tear strips, and consequently of failing to open the package.
In a package derived from the preceding package, in which the corner is also formed by two 45° folds, the parallel tear strips are closer to the center of the package and present an enlargement towards said center so that they are situated very close to the end of the pull corner while the corner is being formed. However, portions of the sides of the 45° folded corner are heat-sealed onto the second sheet, forming a fold that presents greater resistance to tearing. Such a package, when made out of polyethylene (PP), is very difficult to tear because of this fold, which is why that package is made out of oriented polypropylene (OPP).
French patent No. FR 2 362 765 discloses a package in the form of a rectangular parallelepiped provided with a tear strip in the form of a tuning fork, with a very short handle forming the pull tongue for tearing purposes. It is not easy to take hold of that short tongue.